Most of the subject matter of the invention described in the present application was publicly disclosed by the inventors In Gwun Jang and Seung Beop Lee in a paper and a presentation entitled “Layout optimization of the secondary coils for wireless power transfer systems,” submitted to and presented at the IEEE Wireless Power Transfer Conference 2015, held at the University of Colorado, Boulder, Colo., USA, on May 13, 2015; and in a paper and a presentation entitled “Layout optimization of the secondary coils for wireless power transfer systems,” submitted to and presented at the 11th World Congress of Structural and Multidisciplinary Optimization, held in Sydney, Australia, on Jun. 11, 2015. Therefore, the publication or disclosure was made by and/or originated from all members of the inventive entity of the present invention less than one year before the filing date of the present application. A copy of the article is provided in a concurrently filed Information Disclosure Statement pursuant to the guidance of 78 Fed. Reg. 11076 (Feb. 14, 2013).
Embodiments of the inventive concept relate to a method and a system capable of optimizing a layout of a secondary coil for a wireless power transfer.
Wireless power transfer may refer to a contactless power transfer technique in which electrical energy from a primary coil (a transmitter part) induces magnetic field energy and the induced magnetic energy induces electrical energy at a secondary coil (a receiver part). The wireless power transfer is being actively researched and is applied to a variety of applications ranging from electronics to electric vehicles.
There is a growing interest in a wireless power transfer system, which uses a plurality of transmission coils to improve efficiency of the wireless power transfer and guarantee stability thereof, and a wireless power transfer system which use a plurality of receiving coils to charge multiple devices at the same time. Accordingly, many consumers demand a function to charge multiple portable electronic devices rapidly at the same time.
To satisfy the performance of the wireless power transfer about multiple devices, an efficient transfer of the magnetic energy should be secured through the selection of optimal layouts about primary and secondary coils.
A coil layout for a conventional wireless power transfer system may be designed mostly depending on experience and intuition of the designer. This manner is not fit to a coil layout design method for an up-to-date wireless power transfer system which includes a plurality of transceiver systems and should satisfy various constraints (e.g., a transfer capacity, a transfer efficiency, a system mass, a criteria about health hazards, etc.).
For this reason, to implement a wireless power transfer function (multi-source and multi-device based wireless power transfer) being required recently newly, there is required a systematic and efficient coil layout design method which is distinguished from a conventional design method.
The improvement of efficiency of the wireless power transfer system being actively researched may depend on a magnetic resonance manner which is based on the adjustment of inductance, capacitance, and an input frequency.
For the magnetic resonance manner, a change in inductance due to misalignment between primary and secondary coils and an environmental change (e.g., a temperature, etc.) may cause a change in a resonant frequency (e.g., mismatch between an input frequency and a system frequency), thereby lowering the efficiency of system sharply (instability).
With regard to the improvement of the efficiency of the wireless power transfer system and the achievement of the stability thereof, the following approaches have been used to design layouts for primary and secondary coils which are able to generate and maintain a constant magnetic field (e.g., a coupling coefficient and a self-inductance).
With the empirical design approaches, the study is being conducted in the direction of analyzing influence according to the result of arbitrarily changing coil shape and phase, turns, measure, etc.
A conventional technique associated with a change in the coil shape and phase, turns, and measure is disclosed, but since the empirical design approaches depend on the knowledge and intuition of a designer, a more systematic and more effective design methodology is required.
With the design domain search, the study is being conducted to figure out and improve the performance of system through the full design domain search about one or more of a plurality of design variables.
A full design domain search technique about mutual inductance, characteristic impedance, internal resistance, and a resonant frequency has been disclosed. The design domain search is more systematic in design than the empirical design approaches but is inefficient in computation.
As such, the empirical design approaches and the design domain search do not satisfy various constraints (e.g., a transfer capacity, a transfer efficiency, mass, a criteria about health hazards, etc.) For the wireless power transfer system which includes a plurality of transceiver systems and in which a lot of design variables exist, it is impossible to consider all mutual coupling effects.